B918-C918 2018-2023 Ford Mustang GT Fastback 3in Catback Exhaust

Thermal R&D 3 Inch Catback Exhaust Built for the 2018-2023 Ford Mustang GT Fastback

The Thermal R&D B918-C918 is a complete 3 inch catback exhaust system engineered specifically for the 2018-2023 Ford Mustang GT 5.0L Fastback. Mandrel-bent T304 stainless steel tubing replaces the stock cat-back section from the catalytic converter outlets rearward, increasing exhaust flow and deepening the tone without altering emissions equipment. True Helmholtz Technology is built into the muffler design to cancel the resonance frequencies responsible for cabin drone, delivering an aggressive V8 exhaust note under throttle that stays controlled and quiet at cruising speeds. The system uses all OEM hanger locations, requires no cutting or welding, and finishes with 4 inch quad angle-cut tips in your choice of polished stainless or ceramic coated black. Manufactured in Lancaster, California by Thermal Research and Development with a Limited Lifetime Warranty to the original vehicle owner.

Key Features

• 3 Inch T304 Stainless Steel Mandrel-Bent Tubing — Full 3 inch diameter throughout for maximum flow and deep V8 tone
• True Helmholtz Technology — Proprietary resonator design cancels drone at highway cruising speeds
• 4 Inch Quad Angle-Cut Tips — Available in polished stainless (B918-C918) or ceramic coated black (B918-C918-C)
• Direct Bolt-On Installation — Uses all OEM hanger locations, no cutting or welding required
• Emissions Legal — Connects downstream of OEM catalytic converters, no check engine light
• Fastback-Specific Fit — Engineered for the S550 Fastback body, does not fit convertible models
• Limited Lifetime Warranty — To the original vehicle owner, non-transferable, excludes racing and commercial use
• Made in the USA — Manufactured in Lancaster, California

What's Included

• Complete 3 inch catback exhaust system (mid-pipe and muffler sections)
• 4 inch quad angle-cut tips in polished stainless or ceramic coated black
• All necessary OEM-style clamps and hardware
• Thermal R&D installation instructions

Specs

Fitment

Frequently Asked Questions

Does the B918-C918 fit my 2022 Ford Mustang GT Fastback?
Yes. The B918-C918 fits all 2018-2023 Ford Mustang GT Fastback models with the 5.0L V8. It does not fit convertible models.

Does the B918-C918 work with the OEM active valve exhaust system?
No. The B918-C918 is not compatible with Mustang GT models equipped from the factory with the Active Valve Performance Exhaust (AVPE). If your Mustang has the factory active valves, look for a B918-C918 variant that supports that system or contact us before purchasing.

Will there be drone on the highway with this exhaust?
No. True Helmholtz Technology is engineered specifically to cancel the resonance frequencies that cause drone at 65 to 80 mph. Owners consistently report zero drone at highway speeds and deep, aggressive tone under throttle.

What is the difference between the polished and ceramic coated tip options?
The B918-C918 includes 4 inch quad angle-cut polished stainless tips. The B918-C918-C ceramic coated variant includes the same tips with a black ceramic finish that resists heat discoloration and oxidation. Both are the same system; only the tip finish differs.

How much louder is the 3 inch system compared to stock?
Noticeably louder with a deeper, more aggressive V8 tone compared to stock, particularly under full throttle. At idle and light cruise it remains very manageable. The True Helmholtz design keeps it from becoming drone-inducing at highway speeds.

Does this require any cutting, welding, or modification?
No. The B918-C918 is a direct bolt-on replacement using all OEM hanger locations. All necessary clamps and hardware are included. No cutting, welding, or drilling is required.

Does installing this exhaust void my Mustang's warranty?
Under the Magnuson-Moss Warranty Act, a manufacturer cannot void your vehicle warranty solely because you installed an aftermarket exhaust part. A dealer must demonstrate that the aftermarket part caused the specific failure before denying coverage.

What warranty does the B918-C918 carry?
Thermal R&D covers this system with a Limited Lifetime Warranty to the original vehicle owner, non-transferable. The warranty covers defects in materials and workmanship and does not extend to racing, commercial use, or improper installation. Manufactured in Lancaster, California.

Will the tips fit within the factory Mustang GT rear bumper?
Yes. The 4 inch quad angle-cut tips are sized and positioned to fit cleanly within the factory 2018-2023 Mustang GT rear bumper cutouts without modification.

Does this system fit the Ford Mustang Dark Horse or Shelby models?
The B918-C918 fits the standard Mustang GT Fastback 5.0L. The Dark Horse, GT500, GT350, and Mach 1 have different exhaust routing and tip configurations. Contact us to confirm fitment on specialty models before ordering.

Installation Instructions

Apply penetrating fluid to all factory exhaust hangers and clamps before beginning, particularly on higher-mileage vehicles. With the vehicle safely elevated on jack stands, disconnect the stock catback at the catalytic converter outlet clamps and unclip all hanger isolators working from rear to front. Remove the factory system in sections. Install the B918-C918 mid-pipe first, connecting at the OEM catalytic converter outlets and leaving clamps hand-tight. Hang the rear muffler and tip section on the OEM hanger rods, centering the quad tips within the rear bumper cutouts before torquing all clamps to spec. Start the engine and inspect all connections for leaks. No cutting, welding, or drilling is required at any step.

WARNING: This product can expose you to chemicals including nickel compounds, which are known to the State of California to cause cancer and reproductive harm. For more information, go to www.p65warnings.ca.gov.